low marimba
with bass boost/treble reduction is even better
Light rain on leaves
Crashing waves at the beach. Seagulls are little assholes but they add to the effect for me
I can’t decide, there are too many:
Mongolian throat singing with little to no instruments.
The sound of a plane cabin (I think its brown or pink noise)
The fire crackling of a fire place or furnace.
Ocean waves or waterfall or river noise.
Slowly and softly played piano.
A stew slowly cooking.
Sound of gentle brushing your head hair.
I don’t know about most, but generally those “background sound” sort of ambient things are pretty relaxing.
goes looking on YouTube for some examples
Rain: https://www.youtube.com/watch?v=8plwv25NYRo
Lake waves: https://www.youtube.com/watch?v=Se5NjX-cM5I
Ocean waves: https://www.youtube.com/watch?v=WHPEKLQID4U
I think that the shakuhachi, a Japanese bamboo flute, is relaxing to listen to.
finds an example on YouTube: https://www.youtube.com/watch?v=miUKO5g0ONk
Rain and thunder outside while inside in the evening.
Also, due to occupational damage, the sound of an offshore seismic source going off in the distance ever 10-12 seconds. The sound and the low frequency shake of the ship means everything is working as it should.